mls or stock replacement

kpoindex08

Registered User
Today at work I was looking at how much it would cost to change my HG on my 94 5 spd. I like the idea of MLS gaskets but is it worth it? Do they seal better? What are the advantages and disadvantages? I did however notice that the coolant passages are slightly different on the MLS gaskets. Does this impact the performance of my car? I can get the HG set for $160 (employee discount) and I can get the MLS gaskets p# 9262 pt and 9263 pt both for $60 each
 
60 each.. and that INCLUDES your employee discount? not much of a discount if you ask me. I get mls gaskets for $90 total. try a different source.

also, if you switch to an mls, make sure your block surface is smooth enough for that type of gasket, along with your cylinder head surface.
 
from everything I read...
MLS is NOT needed unless you are running some super boost and pushing it REAL HARD. Before doing the MLS you have to get the heads and block cleaned/resurfaced, from what I have read.

A set of Fel-Pro gaskets and new bolts or ARP studs and you should be fine.

Saying that also is assuming you are opening up the exhaust!
10-14lbs of TRUE boost allowed to run through and not 10lbs of boost with 4lbs of back pressure is WAY BETTER and allows gaskets to last longer.
 
Standard Fel Pro gaskets and ARP studs are fine. They will last with boltons with out any issues. I used them on my last motor that was putting down near 300 and running 13.10's with about 18lbs of boost before the 100k bottom end went.
 
Standard Fel Pro gaskets and ARP studs are fine. They will last with boltons with out any issues. I used them on my last motor that was putting down near 300 and running 13.10's with about 18lbs of boost before the 100k bottom end went.

Well there ya go!

Exactly what I have read on here for the last year or so!

MLS is NOT needed.
 
Thanks all for the comments. But the questions were not answered. What are the advantages and disadvantages? Do they seal better? Does the different cooling passage affect the performance of the engine? If I am going to tare it down I want the best solution not an “I used it and it worked “solution. I don’t care if they are not needed. I just care if it is the best rough if I don’t want to do it again. The 94/95 should be decked around 50 RA or better. I have not touched the exhaust it is brand new stainless steel from the manifolds back to the tips.
 
these people have given you solutions. Also use the search function. this subject has been covered many times before. check the block surface for warpage, and for smoothness. an mls gasket is metal, it doesn't have the ability to fill in the imperfections like a paper gasket can. mls gaskets are multi-layer-steel, oem gaskets are composite. mls is stronger than stock, but they cost more, and they need to have the correct surface in order to seal properly.

about the coolant passage, If I remember correctly, doesn't do anything in terms of performance. actually it diverts the coolant away from the rear cylinders, either that or limits the coolant getting to the rear cylinders. which can cause them to run warmer than the rest. but then again. I need to search for the answer to that as well.

basically, just search and you will find the answer.
 
yes thay are solutions but are thay the BEST solution. I have done the searches. Time change, knowledge changes, and so does the product on the market. If every one searched and used information from 3-5 years ago they will be using out of date information and could miss that there is something better out there in today’s time. Also last time I resurrected an old post on a different forum they went ape ~~~~~ and told me to make a new post anyways. So I don’t even bother replying to posts older than a year old. I know what LMS stand for I work at an auto parts store (2 years now) I do have a lot to learn but I know the basics. Also if there was restricted flow to the rear cylinders that would effect performance of the engine. I could not find anything on coolant restrictions on the search function. Also if i do go MLS should i use copper casket sealer or not?
 
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Advantages to the MLS gaskets specifically are their ability to re-seal after head movement.

When driven hard (say 1/4 track, or highway entrance ramp) and detonation occurs (it always occurs in our cars) cylinder pressure spikes. With the limited number of head bolts on our cars, this causes the head to lift ever so slightly to release pressure. The graphite gaskets tend to deform allowing coolant intrusion and eventually failure of the fire ring, typically on the #6 cylinder.

MLS gasksets do not deform, and allow continued sealing even when the head lifts. MLS gaskets have been found to be AS good as o-ringing the heads in sealing the combustion chamber.

ARP head studs are recommended in any case, as they allow for a higher clamping force on the head than could be achieved with bolts. This benefits both MLS and standard Graphite composite head gaskets.
 
The coolant passages on the gaskets are deliberatly small at the front and go bigger to the rear of the block. This forces the coolant to flow through the block front to rear then back to the front through the heads.

Putting the gaskets in backwards will cause the rear to heat up since there won't be any coolant flow back there.

Fraser
 
I like the idea of MLS gaskets but is it worth it? Do they seal better? What are the advantages and disadvantages? I did however notice that the coolant passages are slightly different on the MLS gaskets. Does this impact the performance of my car? I can get the HG set for $160 (employee discount) and I can get the MLS gaskets p# 9262 pt and 9263 pt both for $60 each

ok,
as we have said... either MLS or the Regular ones WORK.

MLS Worth the money? well figure the price of the gaskets, price of machining/resurfacing the block and heads to ensure a good seal surface.
Along with the money to do the work comes the time effort and money associated with pulling the block to send out for the machine work.
So is it worth it?? Depends, WHAT are you looking to do with the car/motor.
IF you are asking about money, worth it to do the MLS, then my guess is you are not ready to spend the money to make the MLS needed. To get to the point of MLS needed... you have to spend ALOT of money in machine work and parts... ALOT!

Advantages vs disadvantages...
well, alot have been said here already but again boils down to REALITY of what you are doing with the car and why.

so take the advise and info you have been supplied and realize...
BOTH WORK FINE! Again, if you are asking about money advantages/disadvantages you are not in need of MLS.

Spend your money on Exhaust, ARP headbolts, and good Fel-Pro gasket set, then look for a 94/95 M90.

IF I sound blunt, oh well. As said, MLS is NOT needed or worth the hassle of doing if you are NOT RACING or pushing ALOT OF BOOST AND HP!
 
my way of determining. Do I ever intend to have the car make more than 300rwhp? No... then stock replacement gaskets and ARP studs. If yes, then MLS (and the associated machine work necessary) and ARP studs.

it is about that simple.
 
the way i see it, ford discontinued our crap gaskets and went to mls gaskets in 97 due to the high rate of head gasket failures they were having

thus if its good enough for Henry, its good enough for decipha
 
Check this out

Greetings, Here is my 1/2 cent worth!
http://www.sccoa.com/forums/showthread.php?t=112315&highlight=machine+finish
"We deck both our heads and blocks to RA 15-25
9642PT-1 (the same for both sides?) Composite
MLS:
9262PT left and 9263PT right"

Rough Average finish of 15, I believe is close to a 400 grit sand paper finish. That is very smooth in machining. My block had enough erosion on the exhaust side of the block and at each end that I didn't feel it would seal. http://www.sccoa.com/forums/showthread.php?t=113927 Post #8. I bought a machinist straight edge and checked the block and heads. They are still true. I just love getting grease under my nails so I pulled the engine and am going to machine the deck to a finish I believe will work. And of course, this is a good excuse to pull the M5R2 and help it along, plus figure out why the clutch is dragging.

You can very easily be into a total rebuild when you start pulling on the MLS gasket thread. Deck the block, now the pistons are coming out of the holes and or hitting the head. Deck the block and surface the heads, enough material has been removed that valve clearance needs to be checked so that there is enough room in the piston pockets for that .500" cam you just decided to install. And it can go on and on and on. Ask me how I know.
Pressure test the heads and check that they are in compliance.
If the deck is true, spray it with copper gasket goop, use composite gaskets.
Stand back and admire your work drinking a really good beer.
Be driving your car at 1/2 - 1/4 the cost and time.
Use the $1500 -$3000 that use didn't spend on doing all the work to use MLS gaskets and starting building a blown 4.6L and make your car the SC that Ford should have built in 1995! (Just had to add that.)

MLS gaskets are the superior solution IMHO. Is it the best bang for the performance and reliability of a stock engine? I doubt it. New exhaust from the exhaust manifolds back, were the exhaust manifold collectors expanded to 2" ID? 2-1/2" downpipes to a good free flowing CATs, and the rest of the recommended sizes and pieces to the bumper? You have received advice from a number of people who have "been there, done that".

A preemptive strike, on your part, is not a bad idea since I am guessing, you know little about the car's history. Doing the HG job before it blows will get you ahead of the curve on one important issue. Getting coolant in the oil will wipe out the bearings. If that happens, you will be in for an overhaul. Get your ducks all lined up. Order the ARP Chevy V6 head studs. Pull your codes and see if your EGR is working. Get a teflon sealing kit for the Intercooler and maybe the kool Teflon gasket set for the SC. Plan on replacing the motor mounts, if this hasn't been done. My oil pan is showing wear on it where it is rubbing a line that comes across the top of the K member. Check the Harmonic Balancer and be prepared to find that it is about to go South on you. Put everything back together knowing you are fixing all the hidden vacuum/boost leaks that are present now. Your engine will stay under the hood, rather than jumping up denting it. Your new really expensive HB will insure that your engine internals stay happy. Your ported out exhaust manifolds will dump a lot more product in your nice shiny SS exhaust system. Since your engine is breathing easier and the ARP studs are providing superior clamping on the composite gaskets, as compared to head bolts, you will enjoy many happy hours flogging the M5R2 and wishing those guys doing the T56 swaps would hurry up and get them done.
-Dave
 
For historical accuracy sake....Ford updated the head gaskets on the 94 SC from what was originally used in 89. The MLS gaskets came later as noted. The 94 headgaskets did seem to have fewer problems than the earliest version. Whether that was because of the revised HG can not be determined since the 94 heads were also redesigned with one side benefit being increase deck rigidity.
 
I'm running the fel pro composite gaskets on my car making 17.5 psi of boost (ported heads, larger valves, larger cam) and making over 300rwhp with no issues. I'm actually going to be upping the boost another pound or so now that I've got a bigger cam in. I'm estimating I'm going to be about 350rwhp.

I believe it has alot to do with managing the detonation these motors have. Stupid things like running 32 degrees of timing with the knock sensor turned off is going to blow head gaskets, and MLS will not save you there. Other dumb things like running 25% OD on a stock blower with a stock IC, stock heads and cam and no tune is going to blow gaskets... and I can add a bunch of other reasons.

It was mentioned earlier how MLS can handle the heads lifting and reseal.... Sure they will reseal, sort of, but count on redoing the gaskets as soon as possible, as they will not totally 100% seal up again. Ask some of the guys that have had that happened to them.

The stock SC motor detonates, especially in cooler weather, and I strongly believe thats what kills the head gaskets after a couple of 100000 miles, which to me isn't all that bad considering what these motors are trying to do.

I mean look at it this way. People are calling these motors absolute crap and screaming switch to v8 because they are more reliable etc. Well, you know what? Lets see what a factory built 5.0L (I'll allow updated with factory built forged internals) will look like with 13 pounds of boost on it that has constant detonation after a couple of 100000 miles on it :cool:. I don't see race built motors being asked to go for 200000 miles in all different aspects of driving conditions out there without a rebuild.

I also like the idea that the head gaskets do blow out, because if something goes wrong, its alot cheaper to replace those than having to replace the whole motor because something else gave way, which usually is catastrophic.

MLS gaskets are better ultimately if you can afford all the work thats involved... but if you are responsible with modding the motor and what you do with it, then the composites will do you good.

Fraser
 
MLS gaskets are better ultimately if you can afford all the work thats involved... but if you are responsible with modding the motor and what you do with it, then the composites will do you good.

Fraser

A great point Fraser. For folks that search around this site I suggest you or Dave work on a FAQ regarding head gasket selection. In the past, there simply wasn't any reliable understanding of how our engine management was working or what the engine was doing. Thus there were tons of assumptions on what was leading to the rash of head gasket failures. People were going so far to o-ring their blocks and switch to copper head gaskets, willing to live with the challenges of these changes because no one really understood what was leading to the failure of the stock gasket.

The understanding and knowledge of these motors has grown exponentially over the past few years. Much of it due to your and Dave's efforts, as well as the failures that had come before.
 
I agree on the FAQ section. I am 20 years old and have owned 2 T-birds done HG on my 96 3.8 changed oil pan gasket and engine mounts on both 96 and 94. I know they are 2 different animals but basically the same. I have worked on cars since I was 10 and owned 12 vehicles in my life time. I restored my first vehicle at 15 (93 dodge Cummins 4x4) after it burnt to the ground so I could drive to school. So I am very mechanically inclined. I did not mean cheapest when I said "is it worth it" I meant would it be worth it if I didn’t want to do it again in the near feature. I all ready bought the fel-pro HG set, Teflon seals and ARP studs. I have replaced all belts, all pulleys, back wheal Barings, all rotors, all pads, most VAC lines, PCV, removed air silencer, rear upper and lower control bushings, all ball joints, right inner tie rod end, power antenna, coil pack, wires, plugs, cam sensor, crank sensor, all front control arms and bushings, all sway bar links, and oil presser switch. But im sure there is lots more to come. After I get her all torn down I will make my decision on the MLS gaskets. I will get the mechanic rule at work tomorrow to see if there is any warpage. Also fel-pro offers an MLS for when you have to re deck the block would it be wise to get these if I do have to re deck the block? Also what is the largest RA MLS gaskets can handle?
 
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